US Presidential hopeful Mitt Romney today made a long-overdue climbdown after he made a diplomatic gaffe about London's readiness to host the Olympics.

Mr Romney told US channel NBC's Today Show: "after being here a couple of days it looks to me like London is ready"

Barack and Michelle Obama earlier threw their support behind the London Olympics after the Republican presidential hopeful’s visit to Britain threatened to go from bad to worse.

The White House said the President had the “utmost confidence” in Britain’s preparations as the First Lady met American athletes this morning at the University of East London, where they have been training for the Games.

“Wow. I can’t believe I am here,” she said. “I am beyond proud. It is a pleasure, a joy and an honour to be here for all of you. I can’t begin to tell you how amazing it is to lead the US delegation to the opening ceremony. Being here is other-worldly for me.”

The Obamas’ upbeat message contrasted with that of Mr Romney who had questioned whether London was ready to stage the Games and if the UK would unite behind them.

With #romneyshambles trending on Twitter, Culture Secretary Jeremy Hunt became the latest British politician to round on Mr Romney.

“We are ready,” Mr Hunt told ITV’s Daybreak. “When we have the opening ceremony tonight and we tell the world that eight of the world’s top 10 sports were either invented or codified in Britain, and only two in America, I hope Mr Romney is watching.”

President Obama’s aides were reported to have been chortling at the way Mr Romney’s three-day visit to Britain went off the rails.

Mr Obama and senior officials in Washington met yesterday to discuss security at the Olympics.

White House press secretary Jay Carney said that during a meeting with staffers, the President had “made it clear that he has the utmost confidence in our close friend and ally, the United Kingdom, as they finalise preparations to host the London Olympics”.

Twitter messages have included: “Mitt Romney isn’t even qualified to represent the U.S. as a tourist” from Path2Enlightment, and “According to my friends in Gloucestershire, Brits are already beginning to call Mitt Romney the American Borat,” from Jason Febery.

The Foreign Policy blog also reported that in his book No Apology, Mr Romney wrote that England “is just a small island. Its roads and houses are small. With few exceptions, it doesn’t make things that people in the rest of the world want to buy.”

Mr Romney sparked the diplomatic row by highlighting in an interview with NBC “a few things that were disconcerting, the stories about the private security firm not having enough people, the supposed strike of the immigration and customs officials, that obviously is not something which is encouraging.”

Mr Romney, who oversaw the Games in Salt Lake City in 2002, also questioned whether all of the UK would come together to “celebrate” the Games.

David Cameron swiftly rebuffed his remarks, stressing Britain’s achievement in delivering the Games in difficult economic times and the euphoria sparked by the Olympic torch as it toured the country.

He added: “We are holding an Olympic Games in one of the busiest, most active, bustling cities anywhere in the world. Of course it’s easier if you hold an Olympic Games in the middle of nowhere.”

As he left No 10, Mr Romney sounded far more supportive of the London Games.

Mayor Boris Johnson roused a crowd of at least 60,000 in Hyde Park last night by saying: “There’s a guy called Mitt Romney who wants to know whether we’re ready. Are we ready? Are we ready? Yes, we are.”